What are some live update best practices?

What are some best practices for developing a weather app that live updates the temperature?

Some things I currently do are:

1. Only update if the user isn't idle (i.e. device is on but user isn't actively using it)
2. Update on an interval (looking for a reasonable time interval to update on here, currently updates every 30 minutes)
3. Minimal API call (wish there was an even simpler one for just "temp"